<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>箭头函数参数默认值</title>
</head>
<body>
  <script>
    /**
     * 箭头函数参数默认值
    */
    function apply (a = 3, b = 5) {
      console.log(a + b);
    }
    apply(5) // 10
    apply(undefined, 10); // 13
  </script>
</body>
</html>